Alkyne removal from hydrocarbon streams

ABSTRACT

CATALYSTS HAVING THE FORMULA (CO2(CO)6L2) OR   (CO(CO)3L2)(CO(CO)4)   ARE EMPLOYED TO REMOVE ALKYNES HAVING FROM 2 TO 20 CARBON ATOMS FROM HYDROCARBON STREAMS.

United States Patent Ofice Patented June 25, 1974 ABSTRACT OF THEDISCLOSURE Catalysts having the formula [CO (CO) *L or are employed toremove alkynes having froml to 20 carbon atoms from hydrocarbon streams.

This invention relates to the removal of alkynes from hydrocarbonstreams.

In one of its more specific aspects, this invention relates to theremoval of acetylene from ethylene streams through the employment of acobalt complex catalyst.

In many instances, the removal of alkynes from hydrocarbon streams isdesirable. There has now been discovered a method of removing alkynesfrom such streams by the employment of a catalyst which is relativelyinsensitive to water and carbon monoxide and by a method which enablesthe simple separation of the hydrocarbon stream from those forms towhich the alkynes are converted.

According to the present invention there is provided a method for theremoval of alkynes from a hydrocarbon stream which comprises contactingthe stream with an effective amount of at least one catalyst selectedfrom the group consisting of [C0 (CO) L and under conditions to removeat least a portion of the alkynes from the feedstream and recovering thehydrocarbon stream, L being as hereinafter defined.

The invention is applicable to the removal of alkynes, both terminal andinternal, of from 2 to about 20 carbon atoms per molecule from C to Chydrocarbon streams and particularly from streams comprising olefins,cycloolefins and conjugated dienes. These hydrocarbon streams can alsocontain alkanes, cycloalkanes, aromatic hydrocarbons and their mixtures.The invention is especially suitable for the removal of acetylene fromethylene streams.

The feedstream needs no pretreatment although it should be reasonablylow in Water content.

The invention is carried out by introducing the feedstream into contactwith a catalyst having either of the two formulas in which formulas Lrepresents a ligand selected from the group consisting of CO, R 1, R PO,R N and pyridine, R being a hydrocarbon radical having 1 to about 12carbon atoms such as alkyl, cycloalkyl, aryl and combinations thereofsuch as alkaryl, aralkyl and the like. Examples of suitable catalysts ofthe formula 2( 6L2] include octacarbonyl dicobalt; hexacarbonylbistri-n-butylphosphine) dicobalt; hexacarbonylbis tri-n-butylphosphineoxide )dicobalt; hexac arb onylbis (pyridine) dicobalt; hexacarbonylbis(triethylamine) dicobalt;

hexacarbonylbis(triphenylphosphine)dicobalt; hexacarbonylbis(tricyclohexylphosphine) dicobalt and the like.

Examples of suitable catalysts of the formula )3 2] )4] includetricarbonylbis(tributylphosphine)cobalt(I) tetracarbonylcobaltate (-I)tricarbonylbis(tricyclohexylphosphine)cobalt(I) tetracarbonylcobaltate(-I);

tricarbonylbis(tributylphosphine oxide)cobalt(I)tetracarbonylcobaltate(-I);

tricarbonylbis(triethylamine)coba1t(I) tetracarbonylcobaltate(-'I)tricarbonylbis(pyridine)cobalt(1) tetraca-rbonylcobaltate(-I)tricarbonylbis(triphenylphosphine)cobalt(I) tetracarbonylcobaltate (-I)and the like.

The feedstream is introduced into contact with the catalyst at atemperature within the range of from about to about 150 0., preferablyat a temperature from about to 130 C. and at a pressure to maintain thereaction mixture, preferably, substantially in the liquid phase althoughthe feedstream can be substantially in the gaseous phase.

The feedstream is passed into contact with from about 0.1 to about 1000gram millimol of catalyst per 100 g. of alkynes contained in thefeedstream, the contact time being up to about 24 hours.

Contact between the feedstream and the catalyst is preferably carriedout by passing the feedstream through a dispersion or solution of thecatalyst in an inert diluent such as alkane, a cycloalkane or anaromatic hydrocarbon.

Following the recovery of the feedstream from the catalyst contact, thefeedstream can be fractionated to separate the products to which thealkynes have been converted.

The best mode for carrying out this invention is indicated by thefollowing example.

EXAMPLE Solution Eflluent stream, wt. percent temperature, C. AcetyleneEthylene Elapsed time, hrs.:

Analyses were by gas-liquid chromatography.

The above data indicate the operability of the method of this inventionover a wide range of temperatures within the range previously set forth.

It will be evident from the foregoing that various modifications can bemade to the method of the invention.

Such, however, are considered within the scope of the invention.

What is claimed is:

1. A method of removing alkynes containing from 2 to about 20 carbonatoms per molecule from a hydrocarbon stream which comprises contactingsaid stream comprising said alkynes with an effective amount of at leastone catalyst selected from the group consisting of wherein L is a ligandselected from the group consisting of CO, R 1, R PO, RN and pyridine,wherein R is a hydrocarbon radical having from 1 to about 12 carbonatoms under conditions to remove at least a portion of said alkynes fromsaid stream and recovering said stream.

2. The method of claim 1 in which said catalyst has the general formula[Co(CO) L and is selected from the group of compounds consisting ofoctacarbonyl dicobalt;

hcxacarbonylbis (tricyclohexylphosphine) dicobalt. hexacarbonylbis(tri-n-butylpho sphine oxide) dicobalt; hexacarbonylbis (pyridine dicobalt;

hexacarbonylbis triethyl amine dicobalt; hexacarbonylbis(triphenylphosphine dicobalt; and hexacarbonylbis(tricyclohexylphosphine) dicobalt.

3. The method of claim 1 in which said catalyst has the general formula[Co(CO) L [Co(CO) and is selected from the group of compounds consistingof 4. The method of claim 1 in which said stream is contacted with saidcatalyst at a temperature within the range of from about 80 C. to about150 C.

5. The method of claim 4 in which said stream is substantially in theliquid phase.

6. The method of claim 4 in which said stream is substantially in thegaseous phase.

7. The method of claim 1 in which said stream is contacted with saidcatalyst at a rate within the range of from about 0.1 to about 1000 grammillimol of catalyst per g. of alkynes in said stream.

8. The method of claim 1 in which said stream is passed through adispersion of said catalyst in an inert diluent.

9. The method of claim 1 in which said stream is passed through asolution comprising said catalyst and an inert diluent.

10. The method of claim 3 in which said catalyst istricarbonylbis(tributylphosphine)coba1t(I) tetracarbonylcobaltate(-I).

11. A method of removing acetylene from an ethylene stream whichcomprises contacting said stream with an effective amount of at leastone catalyst selected from the group consisting of wherein L is a ligandselected from the group consisting of CO, R P, R PO, R N and pyridine,wherein R is a hydrocarbon radical having from 1 to about 12 carbonatoms under conditions to remove acetylene from said stream andrecovering said stream.

12. The method of claim 11 in which said catalyst comprisestricarbonylbis(tributylphosphine)cobalt I tetracarbonylcobaltate(-I)References Cited UNITED STATES PATENTS 3,481,961 12/ 1969 Pregaglia eta1.

3,453,302 7/ 1969 Pregaglia et a1.

260-6839 X 2,636,911 4/1953 Ray 260677 2,851,504 9/1958 Hogan 2606772,401,444 6/ 1946 Welling 260-677 2,418,183 4/1947 MCCOmbie 260677 I2,399,882 5/1946 Morrell et a1. 26068l.5 2,775,634 12/1956 NOWlin 2606773,401,206 9/1968 Wulf et al. 260666 DELBERT E. GANTZ, Primary ExaminerJ. M. NELSON, Assistant Examiner US. Cl. X.R.

- CERTIFICATE OF coaa fcr om a Dated June 5, 197a Patent No, 3,819,739

' Darryl R, Fahey It is certified that error appears in the ebove-identifiedgpatent and that. said letters Patent are hereby correctedas shown below: i

601mm 3, line 16, delete "[Co(00) L and insert therefor c CO) L 1111618, delete hexaearbor zylbistricyclohexylphesphinehicob and inserttherefor hexacarbonylbis(tri n-butylphosphine)dicobaltg Signed andsealed this 5th day of Bw'vermmez.- 1974.,

(SEAL) Atteet:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Conunissioner ofPatents

